THE STUDY OF LASER DRILLING OF POLYMERIC MATERIAL MOHD KHAIRI AZRI BIN SHAPIE Thesis submitted in partial fulfilment of the requirements for the award of the degree of Bachelor of Mechanical Engineering Faculty of Mechanical Engineering UNIVERSITI MALAYSIA PAHANG JUNE 2013
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THE STUDY OF LASER DRILLING OF POLYMERIC MATERIAL
MOHD KHAIRI AZRI BIN SHAPIE
Thesis submitted in partial fulfilment of the requirements
for the award of the degree of Bachelor of Mechanical Engineering
Faculty of Mechanical Engineering
UNIVERSITI MALAYSIA PAHANG
JUNE 2013
vi
ABSTRACT
Polymeric materials is widely used in many applications due to its advantages
character but unfortunately, this polymeric material are fragile and not rigid for their
manufacturing process. In order to overcome this problem, the non-contact laser
drilling process is the best solution. However, poor quality of drill has been rise as
critical issues in industry due to the improper setting of drilling parameters. The
purpose of this study are to study the possibilities of low power laser on drilling
polymeric materials and to identify the optimum parameters in order to obtain a good
geometry of drill hole. There were three different test to be analysed in this analysis
that are depth, kerf width and angle for the laser drilling process. A polymeric
specimen with the thickness of 3 mm were used in this analysis. The Taguchi method
has been applied in this analysis. The results show that the optimum parameter for
the standoff distance is 34 mm while for the optimum drilling time is 10 s is needed
for the depth, kerf width and angle analysis for obtain the best geometry of the hole.
Confirmation test has been done to prove this findings. It is proved that a low power
laser drill machine can be used to drill the polymeric materials and the parameters
stated were the optimum parameters to be used in order to obtain a good geometry
drill hole.
vii
ABSTRAK
Bahan polimer digunakan secara meluas dalam banyak aplikasi disebabkan sifat-sifat
kelebihan tetapi malangnya, bahan polimer ini rapuh dan tidak tegar untuk proses
pembuatan. Dalam usaha untuk mengatasi masalah ini, proses penggerudian tanpa
sentuh laser adalah penyelesaian yang terbaik. Walau bagaimanapun, kualiti
penggerudian laser telah menimbulkan isu-isu kritikal dalam industri kerana
penggunaan parameter penggerudian yang tidak wajar. Tujuan kajian ini adalah
untuk mengkaji kemungkinan laser kuasa rendah untuk menggerudi bahan polimer
dan untuk mengenal pasti parameter yang optimum untuk mendapatkan geometri
yang terbaik bagi lubang gerudi. Terdapat tiga ujian yang berbeza untuk dianalisis
dalam analisis ini iaitu kedalaman, lebar garitan dan sudut untuk proses
penggerudian laser. Satu sampel polimer dengan ketebalan 3 mm telah digunakan
dalam analisis ini. Kaedah Taguchi telah digunakan dalam kajian ini. Keputusan
menunjukkan bahawa parameter optimum untuk jarak ketinggian adalah 34 mm
manakala bagi masa penggerudian optimum adalah 10 s diperlukan untuk analisis
kedalaman, lebar garitan dan sudut untuk mendapatkan geometri yang terbaik
lubang. Ujian pengesahan telah dilakukan untuk membuktikan penemuan ini. Ia
membuktikan bahawa kuasa laser mesin gerudi yang rendah boleh digunakan untuk
menggerudi bahan polimer dan parameter yang dinyatakan adalah parameter
optimum untuk digunakan dalam usaha untuk mendapatkan geometri yang terbaik
bagi lubang gerudi.
viii
TABLE OF CONTENTS
Page
SUPERVISOR’S DECLARATION ii
STUDENT DECLARATION iii
DEDICATION v
ACKNOWLEDGEMENTS vi
ABSTRACT vii
ABSTRAK vii
TABLE OF CONTENT viii
LIST OF TABLE xi
LIST OF FIGURES xii
LIST OF SYMBOL xiv
LIST OF ABBREVIATIONS xv
CHAPTER 1 INTRODUCTION 1
1.1 Introduction 1
1.2 Research Background 2
1.3 Research Objectives 3
1.4 Research Scope 3
1.5 Problem Statement 4
CHAPTER 2 LITERATURE REVIEW 5
2.1 Introduction 5
2.2 Manufacturing Process 5
2.3 Drilling Process 6
2.3.1 Machine Tools of Drilling Process 6
2.3.1.1 Hand Drill 6
2.3.1.2 Laser Drilling 7
2.3.1.3 Micro-electro discharge 7
2.3.1.4 Milling 7
2.4 Laser Drilling 8
2.4.1 Anatomy of Laser Drilling Machine 11
2.4.2 Laser Types 12
ix
2.5 CO₂ Laser 13
2.5.1 CO₂ Laser Working Principle 17
2.5.2 CO₂ Laser Application 20
2.6 CO₂ Laser and Drilling Applications 21
2.7 Polymeric Material 22
2.8 The Taguchi Method for Optimization of Process Parameter 23
2.8.1 Design of Experiment 25
2.8.2 Analysis of Variance (ANOVA) 26
CHAPTER 3 METHODOLOGY 28
3.1 Introduction 28
3.2 Methodology Flow Chart 28
3.3 Laser Drill Machine 30
3.3.1 Laser Drill Machine Development 32
3.3.2 Installation of Limit Switch 33
3.4 Material of the Analysis 34
3.4.1 Properties of the Material 35
3.5 Analysis Parameters 36
3.5.1 Fixed Parameters 36
3.5.2 Variable Parameters 36
3.6 Design of Experiment 37
3.6.1 Taguchi Method 37
3.7 Performing Experiment 40
3.7.1 Experiment Procedures 40
3.8 Evaluation of the Project 42
3.8.1 Experimental Result 42
3.8.2 Drill Hole Evaluation 43
CHAPTER 4 RESULTS AND DISCUSSION 45
4.1 Introduction 45
4.2 Analysis Result (Microstructure Test) 46
4.2.1 The Depth Graph 47
4.2.2 The Kerf Width Graph 48
4.2.3 The Angle Graph 49
x
4.3 Parameters Level 49
4.4 The Taguchi Method for Microstructure Test (Depth) 50
4.4.1 Main Effect (Depth) 51
4.4.2 Main Effect Plot for Mean and S/N Ratio (Depth) 52
4.4.3 The Regression Analysis (Depth) 54
4.4.4 Surface and Contour Plot (Depth) 55
4.5 The Taguchi Method for Microstructure Test (Kerf Width) 57
4.5.1 Main Effect (Kerf Width) 58
4.5.2 Main Effect Plot for Mean and S/N Ratio (Kerf Width) 59
4.5.3 The Regression Analysis (Kerf Width) 61
4.5.4 Surface and Contour Plot (Kerf Width) 62
4.6 The Taguchi Method for Microstructure Test (Angle) 64
4.6.1 Main Effect (Angle) 65
4.6.2 Main Effect Plot for Mean and S/N Ratio (Angle) 66
4.6.3 The Regression Analysis (Angle) 68
4.6.4 Surface and Contour Plot (Angle) 69
4.7 Confirmation Test 70
4.7.1 The Experimental and Prediction Value 71
4.8 Analysis Discussion 74
CHAPTER 5 CONCLUSION AND RECOMMENDATIONS 76
5.1 Introduction 76
5.2 Conclusion 76
5.3 Recommendation 77
REFERENCES 78
APPENDICES 81
Appendix A Picture of Result 81
Appendix B Experiment Result Data 82
Appendix C Gantt Chart 83
xi
LIST OF TABLES
Table No. Title Page
2.1 Mechanical and thermal properties of PMMA sheet 23
2.2 Factors and levels used in the experiment 26
2.3 Example of ANOVA table 27
3.1 Specification of laser drill machine 31
3.2 Properties table of the material 35
3.3 Fixed parameters 36
3.4 Variable Parameters 37
3.5 Experiment layout using L25 orthogonal array 39
4.1 Microstructure test 46
4.2 Parameters level 49
4.3 Parameters and microstructure test (depth) values 50
4.4 The ANOVA 51
4.5 The parameter ranking 52
4.6 The optimum parameter for depth test 54
4.7 Parameters and microstructure test (kerf width) values 57
4.8 The ANOVA 58
4.9 The parameter ranking 59
4.10 The optimum parameter for kerf width test 61
4.11 Parameters and microstructure test (angle) values 64
4.12 The ANOVA 65
4.13 The parameter ranking 66
4.14 The optimum parameter for angle test 68
4.15 Optimum parameter 70
4.16 The experimental and prediction value 71
4.17 The experimental and prediction value for optimum parameter 74
5.1 Best combination parameter for depth, kerf width and angle test 77
xii
LIST OF FIGURES
Figure No. Title Page
2.1 Features of laser-drilled holes 9
2.2 Basic system hardware for pulse laser drilling of thin sheets of
metal, semiconductor or polymers
10
2.3 Schematic representation of the CO₂ laser drilling system used